Methods of manufacturing diamond capsules
Capsules and similar objects are made from materials having diamond (sp 3 ) lattice structures, including diamond materials in synthetic crystalline, polycrystalline (ordered or disordered), nanocrystalline and amorphous forms. The capsules generally include a hollow shell made of a diamond material that defines an interior region that may be empty or that may contain a fluid or solid material. Some of the capsules include access ports that can be used to fill the capsule with a fluid. Capsules and similar structures can be manufactured by growing diamond on suitably shaped substrates. In some of these methods, diamond shell sections are grown on substrates, then joined together. In other methods, a nearly complete diamond shell is grown around a form substrate, and the substrate can be removed through a relatively small opening in the shell.
1. A method for making a capsule, the method comprising:
growing a substantially spherical shell of a diamond lattice material over a spherical form substrate such that the shell covers all of the form substrate, wherein local deviations from smoothness on an outer surface of the form substrate are less than about 4 nm;
after growing the substantially spherical shell:
forming an opening through the shell,
removing the form substrate through the opening, and
closing the opening with diamond lattice material;
forming an access port through the shell;
filling the capsule with a fluid via the access port, wherein filling the capsule includes:
placing the capsule into an environment containing the fluid at a high pressure; and
allowing a pressure equilibrium to be reached between the capsule and the environment; and
after the pressure equilibrium is reached, filling in the access port while maintaining the environment at a lower pressure than the high pressure.
2. The method of claim 1 wherein the diamond lattice material is a polycrystalline or nanocrystalline diamond material.
3. The method of claim 1 further comprising:
machining, chemically modifying, polishing, lapping, or grinding a surface of the form substrate prior to growing said substantially spherical shell of a diamond lattice material.
4. The method of claim 1 further comprising:
machining, chemically modifying, polishing, lapping, or grinding a surface of the shell after growing said substantially spherical shell of a diamond lattice material.
5. The method of claim 1 wherein the opening comprises at most 50% of the shell area.
6. The method of claim 1 wherein the form substrate is made of silicon.
7. The method of claim 1 wherein the act of filling in the access port includes:
charging at least a portion of a surface defining the access port relative to the rest of the capsule such that diamond lattice material growth in the access port is promoted; and
growing the diamond lattice material in the access port.
8. The method of claim 7 further comprising:
adding a dopant into at least a portion of the shell,
wherein the act of charging includes charging the portion of the shell where the dopant was added.
9. The method of claim 1 further comprising:
during the growth of said substantially spherical shell of a diamond lattice material, moving the form substrate so as to obtain even growth of the diamond material over the entire surface of the form substrate.
10. The method of claim 9 wherein moving the form substrate includes moving the form substrate intermittently.
11. The method of claim 9 wherein moving the form substrate includes rolling the form substrate in a rotary track.
12. The method of claim 11 wherein moving the form substrate includes keeping the form substrate in motion continuously.
13. A method for making a capsule, the method comprising:
growing a substantially spherical shell of a diamond lattice material over a spherical form substrate such that the shell covers all of the form substrate, wherein local deviations from smoothness on an outer surface of the form substrate are less than about 4 nm;
after growing the substantially spherical shell:
forming an opening through the shell,
removing the form substrate through the opening, and
closing the opening with diamond lattice material;
forming an access port through the shell; and
filling the capsule with a fluid via the access port, wherein the capsule is filled with the fluid at a first temperature, and
after filling the capsule with the fluid, reducing the temperature of the capsule to a temperature at which the fluid solidifies.
14. A method for making a capsule, the method comprising:
growing a substantially spherical shell of a diamond lattice material over a spherical form substrate such that the shell covers all of the form substrate, wherein local deviations from smoothness on an outer surface of the form substrate are less than about 4 nm;
after growing the substantially spherical shell:
forming an opening through the shell,
removing the form substrate through the opening, and
closing the opening with diamond lattice material,
forming an access port through the shell;
filling the capsule with a fluid via the access port; and
after filling the capsule with fluid, closing the access port.
15. The method of claim 14 wherein closing the access port includes inserting a plug made of the diamond lattice material into the access port.
16. The method of claim 14 further comprising:
forming a valve member operable to open or close the access port.
17. The method of claim 16 further comprising:
filling the capsule with fluid via the access port by placing the capsule into an environment containing the fluid at a high pressure and allowing a pressure equilibrium to be reached between the capsule and the environment; and
after the pressure equilibrium is reached, modifying the capsule environment such that the pressure of the fluid on the valve member closes the access port.